Precipitation of zein by spraying



Apl15,194L `A.c.HoREs|E1-AL PRECIPITATIONLOF ZEIN BY SPRAYING Filed Aug. 18, 1957 Patented Apr.` 15, 1941 PRECIPITATION or zEIN BY srnarme Anthony C. Horesi,Downers Grove, Amos H. Flint,

Chicago, and Lloyd C. Swallen, Pekin, lll., assignors, by mesne assignments, to Corn Products Refining Company, New York, N. Y., a corpora.-

tion of New Jersey i Application August 18, 1937, Serial No. 159,728 y 5 Claims.

This invention relates to the precipitation of zein from its solution, for example, the precipitation of zein in water from an aqueous alcohol solution of the zein, and the dehydration of the precipitated zein; and the primary object of the invention is to provide a new and improved apparatus for effecting this operation, `whereby. the operation is performed more conveniently' and economically and the zein is produced in a more desirable condition than has been possible by apparatuses heretofore used.

Among the more important speciilc objects of the invention are the following:

(l) To bring about precipitation of the -zein Y in astate of high dispersion, for example., with the solids V in the form of a loose mass of ne threads. bers or filaments, instead of as a more or less solid dough, as has been usual heretofore; whereby the solvent is more readily removed lfrom 'the zein, so that the zein thev laments of which will be quite brittle when the'- solvent has been extracted will break up and can be dried in the form of minute particles or granules,

which will not stick together b'ut will forma free owing mass. Heretofore it has been customary to precipitate the zein in the form of a dough andto roll out the dough into sheets and then remove the solvent by soaking the sheets T claimed' in application serial No. 214,512, sled June 18, 1938, as a continuation in Apart hereof. Apparatus embodying the inventionI is shown in the accompanying drawing which is a dia'- grammatic layout of a preferred form f apparatus.

Referring to the drawing, A is a nozzle consisting of an inner tubular member I for the zein solution and an outer tubular member` 2 for compressed air and water; the nozzle members being formed with concentric restricted orifices 3 and 4, respectively. The forward end of the nozzle A is enclosed in a receiving casing 5 from which leads a pipe 6 to the Weir box 'I of a flotation tank B provided at opposite ends with Weirs 8 and 9. A chain drag I0 carries the zein filaments which float on the surface of the liquid in the flotation tank into-a mixing box I'I, preferably provided with a rotating agitator I2. The

zein passes from the mixing box I I, which receives water through pipe I3, over an apron I4 to the in water which is a process attended with sev.

eral inconveniences.

(2) To provide an apparatus for continuously precipitating and dehydrating the zein instead oifby the batch processes ordinarily used hereto ore.

- (3) To provide alconvenient means for regulating the alcohol concentration of the water medium used in the precipitating operation and for recovering and reusing the excess alcohol.

(4) To provide'novel means `-ior precipitating zein from its'solution in which the zein is reduced to a iinely divided state and discharged directly into a body of iiowing water; whereby the zein is in the form of fine threads, bres orillaments,

referred to above, from which the alcohol will be readily extracted and the surface stickiness of the zein bodies so reduced that they will not adhere to each other duringvthe subsequent steps of the process.

(5) To provide in otherrespects a suitable apparatus for carrying out the process as outlined above.l

Other incidental objects' will be adverted to in the following description of what is deemed the preferred embodiment ofthe invention. The

disclosed process is not. claimed herein being receiving vessel I 5 of a vacuum filter C of `the drum and belt type, the belt I6 of which delivers the de-watered zein to a conduit I'I leading to a spray drier D. The lter C is provided with a discharge conduit I8 for nltrate, which filtrate passes into a receiver E provided with a connection I! to the vacuum pump (not shown) of iilter C. The nitrate is withdrawn from the receiver E through pipe`20.by pump 2l and some of it i pumped into the mixing box II, through pipe I3, mentioned above, some of it through pipe 22 to the' induction pipe 23 of the outer nozzle member 2 of the nozzle A, and some of it through pipe 24 to the circulating water in the precipitating system. A large volume of liquid is withdrawn from the flotation'l tank B by pump 26 located in a pipe 21, and -is circulated through the cooler F and pipe'25 into the casing 5 surrounding the nozzle tip. i i

The withdrawal of the precipitating medium through pipe 28 is calculated so as to' maintain a proper alcohol content in -the precipitating medium and a corresponding amount of water is introduced through wash water pipe 29 of the filter C. Preferably compressed air is introduced into the induction pipe 23 of the outer nozzle member 2 through the branch pipe 30 for the purpose of increasing turbulence in the water envelope surrounding the zein stream and v.to aerate the precipitated zein so that it will float in the flotation vessel B.

It will be understood that the apparatus as just described is merely typical. The intention is to c over by patent all equivalents and all moulineations within the scope of the claims appended hereto.

In operation it is preferable to use a relatively heavy solution, one containing between 10 and 30 grams of protein per1004 cubic centimeters of zein solution, although operation within this range is not essential. A suitable solutionis one Whichis obtained by treating the zein extract with enough of a hydro-carbon solvent ofmaize-oil and coloring matter to bring about a separation of the mixture into two liquid phases, the heavier of which contains the zein; this heavierA liquid being used either directly in the precipitating operation or after dilution with al cohol or after removal of oil solvent by distillation. The precipitating medium is cooled in cooler F to a temperature ot substantially in excess of 20 C. and prefera ly below 15 C. in lorder to insure the precipita ion of the zein in a non-sticky state and has preferably an alcohol content of 10 per cent or less by volume. The zein solution orifice of the nozzle made by the sharp taper of the end of tubular member l may be about 115 of an inchin diameter; and the orifice for the-atomizing medium, water and air, made by correspondingly tapering the end of tubular member 2 from 1?; of an inch to 1,/8 of an inch in diameter. The pressure of the zein solution may be from 25 to 40 pounds Iper square inch and its rate of feed 5 to 20 gallons per hour. The pressure oi' the atomizing fluid may be 40 pounds per square inch and its rate of now 100 to 150 gallons per hour. The tapered end of tubular member 2 directs the dlspersing :fluid at high pressure against the stream of zein and brings about the reduction of the `zein into the desired ilne lamentary form. f

These conditions are not to be regarded as limitations. They specify one set of acceptable and preferred operating conditions. A Under these conditions the zein issues from the nozzle in the form' of a stream! of liquid about of an inch in diameter which on contact with the surrounding streamof water from nozzle 2, and due to its velocity and turbulence, is changed into a loose mass of threads or filaments of precipitated zein of about 0.02 to 0.04 of an inch diameter. In this form, and'surrounded as they are by water, the extraction of the rest of the alcohol solvent from the zein takes place very rapidly, so .that the natural stickiness of the zein is reduced. as a result of which the material may be treated without lumping or sticking together during' the subsequent steps of the process. The aqueous medium in which the zein is dispersed is aerated by the air introduced through pipe 30 and this aids in keeping the mass of zein 'filaments in suspension until complete coagulation takes place. When dried, the filaments,

which are of a spongy character, will crumble 6 into -small akes or particles so that the material will be granular and relatively free flowing. The completion ofthe alcohol extraction takes place in the flotation tank B. The zein in the l 65 means for causing a liquid precipitating medium mixing box II o \the flotation vessel is .moved by water intr uced into the box at I3, into the .receiving vessel I5 of the lter C. Here the ma terial is partially'dehydrated. Drying may be completed in any desired manner, as for example, in the spray drier D.

The effectiveness oi' the operation,l both as to ythe quick and complete extraction of the zein lsolvent'and the reduction of the material to a dry, non-sticky, granular state results from the high degree of dispersion of the materialxin the '(5 5 plication of the invention to practice.

water bath, in which it is immersed and suspended immediately after it has been reduced to the fine filamentary state by action of the nozzle.

The following i's a specific example ofthe ap- This example is purely typical and informative. .The operating data might be changed very consider-y ably Without departure from the principles of the invention, as will be evident.

10 Example A nozzle is used .having a solution jet of 11g 4of an inch in diameter and a water jet of 7/54 of an inch in diametenthe zein jet oriilce being 15 placed 11; of an inch behind the water orice.

The concentration of the zein is 28 grams per 100 cubic centimeters of the solution.` The pressure of the zein solution'on the nozzle is 35 pounds per square inch. The water pressure is 40 pounds per square inch. The zein solution the nozzle tip at the rate of 40 gallons per min-4 ute. This circulation is maintained at an alcohol concentration of about 10%, whereas, the filtrate. from filter C has a lower concentration, about 5%. The temperature of the precipitating mediumv used is about 15 C. The zein is precipitated in brous filamentary form and the fibers of coagulated zein rapidly lose all tendency to form` dough on application of moderate pressure. The material can be filtered off readily and yields a mass which crumbles easily but which @still contains about 74% of Water. Drying in the air at room temperature yields a light iluiy zein which dissolves in alcohol with extreme ease. I claim: A l. Apparatus for precipitating zein from its solution and recovering the zein, as a solid, in a nely divided state comprising: an inner zein solution nozzle for forming` a fine stream; a conduit of much larger cross section Vthan the nozzle .15 into which the nozzle projects; an outer tubular nozzle surrounding said zein solution nozzle; means for causing a liquid precipitating medium to flow through said conduit in much larger volume than the flow of'zein solution through the zein nozzle; means for forcing a zein solution through said zein nozzle into the liquid flowing through said conduit whereby Vthevzein is precipitated asa loose, illamentary, liquid, permeable mass; and means for forcing a iiuid through said outer nozzle to bring about tur,

bulence promoting the dispersion of the zein in s the precipitating liquid. 4

2. `Apparatus for precipitating zein from .its

solution and recovering the zein, as a solid, in a Q finely divided state comprising: an inner zein resolution nozzle for forming a ine stream; a conduit ofmuch larger cross section than the nozzle into which the nozzle projects; an outer tubular nozzle surrounding said zein solution nozzle;

is precipitated as a'loose, iilamentary, liquid permeable mass; and means for forcing additional precipitating liquid through said outer nozzle to bring about tuburlence andpromote the dispersion of the zein in the precipitating liquid.

3. Apparatus for precipitating zein from its solution and recovering the zein, as a solid, in a finely divided state comprising: an inner zein solution nozzle for forming a fine stream; a conduit of much larger cross section than the nozzle into which -the nozzle projects; an outer tubular p nozzle surrounding said zein solution nozzle; means for causing a liquid precipitating medium to iiow through said conduit in much 'larger volume than the iiow of zein solution through said zein nozzle; means for forcing a zein solution through said zein nozzle whereby the zein is precipitated as a loose, nlamentary, liquid permeable mass; means for forcing air through said outer nozzle to aerate the zein and thereby cause it to float; a flotation vessel connected with said conduit to receive said filamentary mass and precipitating liquid from said conduit; and means for removing from the flotation vessel zein oated therein through action of said air.

4. Apparatus for precipitating zein from its solution and recovering the zein, as a solid, in a nely divided state comprising: a zein solution nozzle for forming a fine stream; a. conduit of much larger cross section than the nozzle into which the nozzle projects; means for causing a liquid precipitating medium to ow through said conduit in much larger volume than the flow of zein solution through the zein nozzle; means for forcing zein solution through said nozzle into the precipitating liquid in said conduit whereby the zein is vprecipitated as a. loose, liquid permeable, illamentary mass; a flotation vessel co1. nected to said conduit to receive the lamentary zein mass and precipitating liquid; andmeans 4 finely divided state comprising: a zeinsolution nozzle for forming a fine stream; a conduit of much larger cross section than the nozzle into' which the nozzle projects; means for causing a liquid precipitating medium to `flow through said conduit in much larger volume than the flow of zein solution through the zein nozzle; means for forcing zein solution through said zeinnozzle into the precipitating liquid in said conduit, whereby the zeinis precipitated in a loose, liquid permeable, lamentary mass; a iiotation vessel connected to said conduit to receive the lamentary zein mass and precipitating liquid from said conduit; means for injecting air finto the precipitating medium to cause the iilamentary mass to float in the flotation vessel; and means for cooling the precipitating liquid to maintain `a yrelatively low temperature during contact of the precipitating liquid with the zein.

ANTHONY C. HoREsi. Aivios H. FLINT. LLOYD c. SWALLEN. 

